Kolkata, Feb 24 (IANS): The West Bengal government has slapped show cause notices on four hospitals for discharging swine flu patients without treatment, an official said Monday.

Three of the offending hospitals are situated in the city. Another one is in the suburbs.

"There are allegations that these hospitals had released patients when they came to know they have been infected by the H1N1 virus that causes swine flu. None of the patients were fit to be discharged," said a state health department official.

The government has started a probe.

The state-run hospitals are under tremendous strain with many of the private hospitals refusing to treat patients. Most of the adult patients have been crowding the National Institute of Cholera and Enteric Diseases, with the B.C. Roy Memorial Children's Hospital taking care of the kids.

Addressing questions in the state assembly, Minister of State for Health Chandrima Bhattacharya said it was a matter of concern that private health facilities were discharging swine flu patients and referring them to government hospitals.